XPS 8500 multi monitor issue (onboard plus AMD Radeon)
I have an XPS 8500 desktop with an AMD Radeon graphics card. I have monitor 1 connected to the onboard VGA port, and monitor 2 connected to the AMD Radeon card via DVI. I have multi-display enabled in the BIOS. When I boot (into Win 7 Pro) I see the Windows startup logo on monitor 1, then the Windows login screen is displayed on monitor 2. After logging in monitor 2 becomes the primary display, while monitor 1 continues to display the Windows startup logo.
When I go into the Connect External Display setup I see both monitors listed in the dropdown list, but when I select monitor 1 (the onboard VGA) and click "Identify" I only see a "2" displayed on monitor 2 - nothing on monitor 1. Nothing I try in the External Display setup will allow me to use monitor 1, either as an extended display or as a duplication of the primary display. It simply displays the Windows startup logo the whole time. It's as if Windows recognises the onboard VGA adapter when it starts the boot process, then loses access to it as the boot process progresses.
Device Manager lists the onboard VGA display adapter as "Video controller (VGA Compatible)". When I try to disable it the Device Manager applet locks up, requiring a forced reboot to recover.
Any idea how I can get Windows to recognise both monitors after booting?